11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_GC_G1_G1SURVRATEGROUP_HPP
26 #define SHARE_GC_G1_G1SURVRATEGROUP_HPP
27
28 #include "gc/g1/g1Predictions.hpp"
29 #include "utilities/numberSeq.hpp"
30
31 class SurvRateGroup : public CHeapObj<mtGC> {
32 size_t _stats_arrays_length;
33 double* _accum_surv_rate_pred;
34 double _last_pred;
35 TruncatedSeq** _surv_rate_predictors;
36
37 size_t _num_added_regions; // The number of regions in this SurvRateGroup
38
39 void fill_in_last_surv_rates();
40 void finalize_predictions(const G1Predictions& predictor);
41
42 public:
43 static const int InvalidAgeIndex = -1;
44 static bool is_valid_age_index(int age) { return age >= 0; }
45
46 SurvRateGroup();
47 void reset();
48 void start_adding_regions();
49 void stop_adding_regions();
50 void record_surviving_words(int age_in_group, size_t surv_words);
51 void all_surviving_words_recorded(const G1Predictions& predictor, bool update_predictors);
52
53 double accum_surv_rate_pred(int age) const {
54 assert(_stats_arrays_length > 0, "invariant" );
55 assert(is_valid_age_index(age), "must be");
56 if ((size_t)age < _stats_arrays_length)
57 return _accum_surv_rate_pred[age];
58 else {
59 double diff = (double)(age - _stats_arrays_length + 1);
60 return _accum_surv_rate_pred[_stats_arrays_length - 1] + diff * _last_pred;
61 }
62 }
63
64 double surv_rate_pred(G1Predictions const& predictor, int age) const {
65 assert(is_valid_age_index(age), "must be");
66
|
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_GC_G1_G1SURVRATEGROUP_HPP
26 #define SHARE_GC_G1_G1SURVRATEGROUP_HPP
27
28 #include "gc/g1/g1Predictions.hpp"
29 #include "utilities/numberSeq.hpp"
30
31 // A survivor rate group tracks survival ratios of objects allocated in the
32 // heap regions associated to a set of regions (a "space", i.e. eden or survivor)
33 // on a time basis to predict future survival rates of regions of the same "age".
34 //
35 // Every time a new heap region associated with a survivor rate group is retired
36 // (i.e. the time basis), it gets associated the next "age" entry in that group.
37 //
38 // During garbage collection G1 keeps track how much of total data is copied out
39 // of a heap region (i.e. survives), to update the survivor rate predictor of that age.
40 //
41 // This information is used to predict, given a particular age of a heap region,
42 // how much of its contents will likely survive to determine young generation sizes.
43 //
44 // The age index associated with a heap region is incremented from 0 (retired first)
45 // to N (retired just before the GC).
46 //
47 // To avoid copying around data all the time when the total amount of regions in
48 // a survivor rate group changes, this class organizes the arrays containing the
49 // predictors in reverse chronological order as returned by age_in_group(). I.e.
50 // index 0 contains the rate information for the region retired most recently.
51 class G1SurvRateGroup : public CHeapObj<mtGC> {
52 size_t _stats_arrays_length;
53 double* _accum_surv_rate_pred;
54 double _last_pred;
55 TruncatedSeq** _surv_rate_predictors;
56
57 size_t _num_added_regions; // The number of regions in this survivor rate group.
58
59 void fill_in_last_surv_rates();
60 void finalize_predictions(const G1Predictions& predictor);
61
62 public:
63 static const int InvalidAgeIndex = -1;
64 static bool is_valid_age_index(int age) { return age >= 0; }
65
66 G1SurvRateGroup();
67 void reset();
68 void start_adding_regions();
69 void stop_adding_regions();
70 void record_surviving_words(int age_in_group, size_t surv_words);
71 void all_surviving_words_recorded(const G1Predictions& predictor, bool update_predictors);
72
73 double accum_surv_rate_pred(int age) const {
74 assert(_stats_arrays_length > 0, "invariant" );
75 assert(is_valid_age_index(age), "must be");
76 if ((size_t)age < _stats_arrays_length)
77 return _accum_surv_rate_pred[age];
78 else {
79 double diff = (double)(age - _stats_arrays_length + 1);
80 return _accum_surv_rate_pred[_stats_arrays_length - 1] + diff * _last_pred;
81 }
82 }
83
84 double surv_rate_pred(G1Predictions const& predictor, int age) const {
85 assert(is_valid_age_index(age), "must be");
86
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